2,6-二(苯并咪唑-2′)吡啶与钴(Ⅱ)的显色反应

Chromogenic Reaction of 2,6-Bis(Benzimidazol-2′-yl) Pyridine with Cobalt(Ⅱ)

在 (CTMAB)存在下 ,在 p H =3.5— 4 .5的 HAc- Na Ac缓冲溶液中 ,2 ,6 -二 (苯并咪唑 - 2′)吡啶(H2 Bzimpy)与钴 ( )形成稳定的 3∶ 1配合物 ,其最大吸收波长为 36 0 .6 nm,表观摩尔吸光系数为 4 .4 6 7× 1 0 4L· mol-1 · cm-1 ,钴 ( )的质量浓度在 0— 2 0μg/ 2 5 m L范围内服从比耳定律。该法用于维生素 B1 2 和含钴分子筛中微量钴的测定 。

In the medium of HAc NaAc with pH 3.5—4.5,2,6 bis(benzimidazol 2′ yl) pyridine reacts with cobalt(Ⅱ) and forms a 3∶1 stable green complex with a maximum absorption wavelength at 360.6nm and the apparent molar absorptivity of 4.467×10 4L·mol -1 ·cm -1 .Beer's law is obeyed in the range of 0—20μg/25mL for Co(Ⅱ).The method was used for the direct determination of cobalt in VB12 and molecular sieve containing Co with satisfactory results.